TAF15 and Ewing sarcoma: FUS is highly related to EWSR1, and both are members of the FET (FUS/TLS, EWS, and TAF15) family of RNA binding proteins, while FLI1 and its related genes are members of the ETS family of DNA binding proteins, and together the “FET-ETS” fusions represent nearly all cases of Ewing sarcoma.